Elastic-fluid machine



Feb. l0, 1931. J. A; DEMPSTER 1,792,288

` ELASTIC FLUID MACHINE Filed April 24. 1929 John A. Dempster, be mac/YMn Patented Feb. 10, 1931 UNETE @gpg COMPANY, A conronarronzor nnwyonxELASTICI-FLUID MACHINE Application tiled April 24,

The present invention relates to elastic Vfluid turbines andparticularly to an improved structure and arrangement for attachingdiaphragm packings to a turbine shaft.

This invention is particularly applicable to tai-bine rotors havingwheels or discs integral with the shafts although the invention is notlimited thereto. Due to the fact-.that the discs are integral with theshaftsit is impossible to assemble solid packing rings on the shaftv byslip ding them over the end of the shaft in the usual manner. Theinherent difficulty in the case` of assembling composite packing ringslies in fastening the same to the rotor. The: present-invention isdirected to an iinproved structure of the packing elements and shaftswhereby these elements may be assembled4 and fastenedA in a satisfactorymanner. For a consideration of what l believe to be novel Yand myinvention, attention is directed to the accompanying description and theclaims appended thereto.

In. the drawing-Fig. 1 is a central sectional Y View of a turbine rotorand stator with packing according to my invention applied tothe rotor.Figs. 2 and 3 are end views of packing as applied to the turbine shaft,the latter being shown in section. Fig. 4 is a detail perspectiveview-of a packing element and a part of the turbine rotor.

Referring to the drawing, 5 indicates a turbine shaft or rotor havingintegral discs or bucket carryingv wheels 7. In Fig. 1 aV diaphragm 8 isshown disposed. between adjacent wheels and carrying a packing annulus9.

According tomy invention I provide an annular T-shaped dovetail slot 10on the circumference of the shaft 5, thus forming apposed under-cutgrooves 11, located a suitable distance from the top of slot 10, andannular flanges 12. Radial passages 13 cut away each flange 12 at twospaced points as illustrated in Figs. 2 and 3. A packing annulus or ring15 of composite nature has an inverted T- shaped dovet-ail portion 16and a face portion 17. Annular grooves 18 are cut in the sides of ring15 and radial, equally spaced passages 19 extend from grooves 18 throughthe flanges of the dovetail portion 16. The width of each in Figs. 2 and3 192@v Serial 'No.\357 ,832 f v passage 19 is made equalv to thedistance between adjacent passages 13.3--For `thepurpose of assembly onshaft 5, `thering 15 is divided into similar sectors 2O withradialdivisions occurring midway between'adjacentpassages 19 The. passages 13in theflanges 1 2 abovementioned .are spaced sothat the distancebetweentheir outside y length of the annular groove .1 8 ofa singlesector. The portion o f each the passages 13 forms a lug,.de signatedv2l which is reduced `in circumferential length to .slightlyllessthanthe length of passages 19 soy that each sectori20 mayslideradially into place'then circumferentially to engage thedovetailportion. 16

l with the flanges12. A hole 2 2 is ldrilled rafdially in shaft 5,'.thecenteroifsaid-h'O-. being in alignment with the margins of the flanges12and the adjacent Yslots 13. The hole 22 is threaded vto receivev a'.threaded pin 2 3.f One sector 2O has a hole 24cu`tV midway of itsvannular length `and -inalignment ,with theholc 22..' A sufficientnuinberof'sectors 2Q are .as-

sembled to'fornrfa completeannulus then all4 flange 1 2 between marginsis equal. to the are moved circumfere'ntia lly until the holes 22and 24register. Thepin 2S,.threaded 'at vvits end, is turned` into member 5untilit lies below the surface of faceportion 17. The metal adjacent thehole 24:l yis'then peened over thepin to lockit'in position. The ring 15is thus held from radial movementaby Vianges 12 ,and fromcircumferential 1 movement by pin 23.

In connection with 'turbines of this type the packing ring15 onl theshaft cooperates with the packing member y9 carried by the diaphragm 8to prevent leakage'between the bore ofthe diaphragm and the shaft. Toproperly prevent leakage the packings have to be spaced with such asmall clearance that a disturbance of the rotor 5 may cause rubbing.This necessitates some provision for dissipating the heat producedbyrubbingbeforethe i shaft becomes heated suiciently to cause bowing ofthe same. To this end, teeth 25 are cut in the adjacent faces of packingmembers9 and 15 to increase the surface area of the bearing faces inContact with the steam in the turbine. The sectors 2O are also providedkwith clearance spaces 26 between the face portions 17 and the flanges12 and clearance spaces 27 and 28 at the sides and base of the dovetailportion 16 as shown in Fig. 1. These clearance spaces are provided toreduce the area of contact between the sectors and the rotor so that themajor portion of the heat produced, in case rubbingoccurs, Will-be disnsipated to the steam by convection rather than Y be Vconducted to thelrotor.v Y

In accordance With the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to repre# sent the best embodimentthereof, but I desire to have it understood that the vapparatus shown isonly illustrative and that the invention may be carried out by othermea-ns.

What I claim as new andv desire to secure by Letters Patent of theUnited States, is:

1. In an elastic uidturbine, a rotor hav-l ing an annular dovet-ailedslot A.cut therein forming flanges on the rotor, said flanges being eachprovided with radially extending slots providing a lug between theslots, a packing ring comprising sectors having dovetailed 'basesforming flanges thereon, said flanges beingof a length to pass throughysaid slots and being providedv With slots of a Width to permit of' thepassage of said lugstherethrough,'-yvhereby When the Vringvof sectorshas been assembled in said yrotor slot, said ring may be turned asaWhole to bring a sector flange undersaid lug.`

2. In an elasticflui l'turbi Y e, a' rotor having an annulardovetailedcut therein formingfianges on the rotor, said flanges 'beingeachv providedV with radially Aextending slots providing a lug betweenthe slots, a packing 'ring comprising sectors having dovetailed basesforming flanges thereon, said flanges being of a length to passthroughsaid slots and being provided with slots of a Width to permit of thepassage of said lugs therethrough, whereby when the ring of sectors hasbeen assembled in Asaidrslot, said ring may be turned as a Whole tobring a sector fiance under'said lug, andV means to lock-,said pac ingring in place When a sector under said slot lug.

In Witness whereof I have hereunto set my hand this 23rdV day of April,1929. Y n

- JOHN A. DEMPSTER..

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